This invention is directed to seals of the kind employed for retaining lubricant and excluding foreign matter from the vicinity of the bearing surfaces between relatively moving parts. In particular, this invention is directed to face-type seals wherein sealing is accomplished by mating surfaces of relatively rotating seal parts of relatively hard material.
Numerous sealing configurations are available to provide rotatable seals between stationary and rotating members in environments such as those of track type vehicles, etc. Typical rotatable seal configurations are described in U.S. Pat. No. 3,108,648 to Kupfert et al.; 3,463,560 to Reinsma et al.; 3,524,654 to Hasselbacher et al., and 3,540,743 to Ashton, all assigned to the assignee hereof.
Such configurations generally employ dual cones and seal rings with axial loading of the seal rings accomplished by means of resilient load rings or torics. Tapered conical or inclined loading surfaces are formed along the outside diameter of the seal rings to receive the torics. A corresponding confronting inclined loading surface is positioned in parallel relation with the tapered surface of the seal ring so as to contain the toric therebetween. Axial loading of the seal rings is thus accomplished through the axial loading of the torics.
The present invention is described and illustrated herein in its application to the track roller of a track-type tractor which is subject to operation in dirt and dust environments which are highly destructive to seals. In an alternate embodiment, it is shown in application to a hinge joint, such as may be found in similar environments and in particular on track-type tracks.
It is well known that failure of track roller seals causes failure and destruction of other components of a roller long before expiration of its intended service life. Therefore, the improvement of seal life is of paramount importance in track roller and track design.
It should be noted that while the present invention as hereinafter described is in connection with tractors and particularly with tracks and track rollers, it may be more widely used. That is to say, the invention may be applicable to other usages which include seals of the type described.
Currently the surface of the member having a confronting inclined surface opposite the like surface of a duo-cone seal is machined from the generally ferrous material of the member, such as a track roller hub member. The surface is irregular and special tooling is needed to form the surface. Since the material that is involved is generally ferrous, oxidation occurs when it is exposed to the atmosphere and is subject to external loading. This oxidation results in a degradation of the surface and a possible loss of seal effectiveness.